The present invention relates to venous reservoir holder assemblies, and more specifically to a reservoir mounting bracket for use in containing venous blood during cardiopulmonary bypass surgery.
A cardiopulmonary bypass is a surgical technique for diverting a patient's blood around the heart and lungs. The blood flow is directed away from the patient at the entrance to the right atrium of the heart, conditioned by mechanical means and then recirculated into the patient at the aorta. By circulating the extracorporeal blood through an oxygenator, an apparatus for introducing oxygen into the blood during extracorporeal circulation, the oxygenated blood can be recirculated in vivo.
As heart surgery employing extracorporeal circulation has become more widely accepted, the demand for the products required to perform such procedures has grown rapidly. Thus, numerous arrangements have been proposed for supporting and manipulating the venous blood during in vitro oxygenation. Such arrangements include various collapsible and expandable containers working under the influence of a vacuum and in conjunction with movable rigid plates.
One such venous reservoir bag support assembly is the Cobe Closed Venous Reservoir Bag, commercially available from Cobe Cardiovascular, Inc. in Arvada, Colo., and disclosed in UK Patent Application GB 2 245 176 A. The Cobe reservoir bag support assembly comprises a venous reservoir bag assembly mounted in a support assembly. The venous reservoir bag assembly has a plate with the venous reservoir bag being carried by the plate. The support assembly has a back plate and a front plate, the two plates being movable relative to each other.
The bag assembly is mounted with its plate in facing relation with one of the back and front plates so that the bag is located between its plate and the other plate. The Cobe Closed Venous Reservoir Bag is limited in that it supports a single reservoir bag size, leading to inefficiencies because blood reservoirs function most effectively when filled. Further, the Cobe Closed Venous Reservoir Bag requires that an oxygenator be separately mounted in the vicinity of the reservoir bag.
Another reservoir bag support system is disclosed in U.S. Pat. No. 4,943,288. This system includes a flexible bag having an external frame with locking elements to retain the bag in an extended position when the bag is being filled, with the locking elements being displaceable to permit the bag to collapse during the reinfusion process. The prior art also discloses alternative arrangements for supporting reservoir bags externally, such as U.S. Pat. Nos. 4,573,992 and 4,466,888.
Prior reservoir bag support systems have proved to be relatively inflexible. First, prior systems support only a single size reservoir bag. Because handling characteristics of the venous reservoir improve with increased reservoir volume, the reservoir functions most effectively when full. Thus, selecting the appropriate size venous reservoir for a patient's needs is critical. Prior art systems do not always allow proper reservoir selection as they only support a single reservoir size. Additionally, prior systems do not support both flexible and rigid blood reservoirs. Further, prior systems require that the blood reservoir be mounted to the support system at the point of use, namely in the operating area. Finally, prior systems require that the oxygenator be mounted separately from the reservoir bag support system in a limited number of positions. These limitations have resulted in prior blood reservoirs support systems that are expensive, difficult to handle and inconvenient and complicated to operate.